LP6218 POWER | Alldatasheet

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Technical content

Features

 Up to 94% efficiency  Output to Input Disconnect at Shutdown Mode  Shut-down current:<1uA  Input and Output voltage Up to 24V  Internal Compensation, Soft-start  1MHz fixed frequency switching  High switch on current:2.1A  Available in SOT23-6 Package Typical Application Circuit VIN SW VIN EN GND FB 22uF 22uF NC 110K 15K 4.7uH VOUT 500K Diode Marking Information Device Marking Package Shipping LP6218 SOT23-6 3K/REEL Marking indication: Y:Production year W:Production period X:Production batch

LP6218 May.-2017 Email: marketing@lowpowersemi.com www.lowpowersemi.com Page 2 of 9 Preliminary Datasheet LP6218 Functional Pin Description Package Type Pin Configurations SOT23-6 1 2 3 456 LP6218 Pin Name Description 1 SW switching pin. 2 GND Ground. 3 FB Regulation Feedback Input. Connect to an external resistive voltage divider from the output to FB to set the output voltage. 4 EN Regulator ON/OFF Control Input. A logic high input(VEN>1.4V) turns on the regulator. A logic low input(VEN<0.4V) puts the LP6218 into low current shutdown mode. 5 VIN Power Supply pin. 6 NC No connecter.

LP6218 May.-2017 Email: marketing@lowpowersemi.com www.lowpowersemi.com Page 3 of 9 Preliminary Datasheet LP6218 Function Block Diagram FB EN SHUTDOWN CIRCUITRY UVLO SOFT START CONTROL AND DRIVER LOGIC SLOPE COMPENSASIONOSCILLATOR OVP VIN SW GND OTP SHORT CIRCUIT COMP. Error Amp. PWM COMP. CURRENT SENSE AMP. 10μA 0.3V 0.6V Σ Absolute Maximum Ratings Note 1 Note 1. Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Thermal Information ESD Susceptibility

LP6218 May.-2017 Email: marketing@lowpowersemi.com www.lowpowersemi.com Page 4 of 9 Preliminary Datasheet LP6218

Electrical Characteristics

(VIN=3.3V, VOUT=5V, CIN=22uF, COUT=22uF, L=4.7uH, R1=110K, R2=15K) Parameter Condition Min Typ Max Units Supply Voltage 2 24 V Output Voltage Range 2.5 24 V Supply Current(Shutdown) VEN=0V, VSW=5V 1 μA Supply Current VFB=0.7V 0.3 mA Feedback Voltage 0.588 0.6 0.612 V Feedback Input Current VFB=1.2V 50 nA Switching Frequency 1 MHz Maximum Duty Cycle 80 90 95 % EN Input Low Voltage 0.4 V EN Input High Voltage 1.4 V Switch MOSFET Current Limit 2.1 A High-side On Resistance VOUT=3.3V 220 300 mΩ

LP6218 May.-2017 Email: marketing@lowpowersemi.com www.lowpowersemi.com Page 5 of 9 Preliminary Datasheet LP6218 Typical Operating Characteristics (CIN=22uF，COUT=22uF，TA=25℃，unless otherwise noted) VIN=3V,VOUT=5V,IOUT=50mA,CH1=VSW,CH2=△VOUT VIN=3V,VOUT=5V, IOUT=200mA,CH1= VSW,CH2=△VOUT VIN=3V,VOUT=5V,IOUT=500mA,CH1= VSW,CH2=△VOUT VIN=3V,VOUT=5V, IOUT=1A,CH1= VSW,CH2=△VOUT

LP6218 May.-2017 Email: marketing@lowpowersemi.com www.lowpowersemi.com Page 6 of 9 Preliminary Datasheet LP6218 VIN=5V,VOUT=12V,IOUT=50mA,CH1= VSW,CH2=△VOUT VIN=5V,VOUT=12V, IOUT=100mA,CH1= VSW,CH2=△VOUT VIN=5V,VOUT=12V,IOUT=300mA,CH1= VSW,CH2=△VOUT VIN=5V,VOUT=12V, IOUT=600mA,CH1= VSW,CH2=△VOUT

LP6218 May.-2017 Email: marketing@lowpowersemi.com www.lowpowersemi.com Page 7 of 9 Preliminary Datasheet LP6218 Operation Information The LP6218 uses a fixed frequency, peak current mode boost regulator architecture to regulate voltage at the feedback pin. At the start of each oscillator cycle the MOSFET is turned on through the control circuitry. To prevent sub -harmonic oscillations at duty cycles greater than 50 percent, a stabilizing ramp is added to the output of the current sense amplifier and the result is fed into the negative input of the PWM comparator. When this voltage equals The output voltage of the error amplifier the power MOSFET is turned off. The voltage at the output of the error amplifier is an amplified version of the difference between the 0.6V bandgap reference voltage and the feedback voltage. In this way the peak current level keeps the output in regulation. If the feedback voltage starts to drop, the output of the error amplifier increases. These results in more current to flow through the power MOSFET, thus increasing the power delivered to the output. TheLP6218 has internal soft start to limit the amount of input current at startup and to also limit the amount of overshoot on the output. Setting the Output Voltage Set the output voltage by selecting the resistive voltage divider ratio. The voltage divider drops t he output voltage to the 0.6V feedback voltage. Use a 100K resistor for R2 of the voltage divider. Determine the high-side resistor R1 by the equation: VOUT = ( R1 / R2 + 1 ) x VFB Current Limitation The internal power-MOS switch current is monitored cycle-by-cycle and is limited to the value not exceed 2.1A(Typ.). When the switch current reaches the limited value, the internal power -MOS is turned off immediately until the next cycle. Keep traces at th is pin as short as possible. Do not put capacitance at this pin. Inductor Selection For a better efficiency in high switching frequency converter, the inductor selection has to use a proper core material such as ferrite core to reduce the core loss and choose low ESR wire to reduce copper loss. The most important point is to prevent the core saturated when handling the maximum peak current. Using a shielded inductor can minimize radiated noise in sensitive applications. The maximum peak inductor current is the maximum input current plus the half of inductor ripple current. The calculated peak current has to be smaller than the current limitation in the electrical characteristics. A typical setting of the inductor ripple current is 20% to 40% of the maximum input current. If the selection is 40%, the maximum peak inductor current is The minimum inductance value is derived from the following equation: Depending on the application, the recommended inductor value is between 2.2μH to 10μH.

LP6218 May.-2017 Email: marketing@lowpowersemi.com www.lowpowersemi.com Page 8 of 9 Preliminary Datasheet LP6218 Diode Selection To achieve high efficiency, Schottky diode is good choice for low forward drop voltage and fast switching time. The output diode rating should be able to handle the maximum output voltage, average power dissipation and the pulsating diode peak current. Input Capacitor Selection For better input bypassing, low -ESR ceramic capacitors are recommended for performance. A 10μF input capacitor is sufficient for most applications. For a lower output power requirement application, this value can be decreased. Output Capacitor Selection For lower output voltage ripple, low -ESR ceramic capacitors are recommended. The tantalum capacitors can be used as well, but the ESR is bigger than ceramic capacitor. The output voltage ripple consists of two components: one is the pu lsating output ripple current flows through the ESR, and the other is the capacitive ripple caused by charging and discharging. Layout Guideline For high frequency switching power supplies, the PCB layout is important step in system application design. In order to let IC achieve good regulation, high efficiency and stability, it is strongly recommended the power components should be placed as close as possible. The set races should be wide and short. The feedback pin and the n works of feedback and compensation should keep away from the power loops, and be shielded with a ground trace or plane to prevent noise coupling. Input and Output capacitors should be placed close to the IC and connected to ground plane to reduce noise coupling.

LP6218 May.-2017 Email: marketing@lowpowersemi.com www.lowpowersemi.com Page 9 of 9 Preliminary Datasheet LP6218 Packaging Information